This communication reports the first ever use of the over ocean evaporation duct to implement a high-capacity radio link from the Australian mainland to the Great Barrier Reef (GBR), North Queensland, Australia. Conventional long-distance radio communication techniques such as high-frequency (HF) radio, satellite, or cell phone are either too slow or too expensive to operate continuously in this situation. A microwave radio link overcomes these problems but would generally not be viable due to the limited range possible with a standard line-of-sight microwave link. This communication shows that by properly choosing the antenna height and operating frequency though, it is possible to trap signals in the ocean evaporation duct and substantially extend the propagation range. A 78-km link that operates at a frequency of 10.6 GHz and provides a data rate of 10 Mb/s has been established to verify the technique. The communication also provides preliminary results of the measured performance of this link and a comparison with existing radio propagation models.

Backfilling and injection of granular materials into mining induced voids, separated beddings, and cracks, as either diluted slurry or concrete paste, is widely used to control coal mine subsidence. As a viable environmental solution, mine waste and rejected materials from underground coal seams are used in both backfilling and injection mine operations. During longwall mining, the grout slurry is pumped into the separated beds of the fractured rock mass through a pipeline connected to a central vertical borehole, which is drilled deep into the interburden rock strata above the coal seam. Either as dilute slurry or thick paste or cake, the fill material normally needs to travel a significant distance in a long pipeline. A blockage can occur in the pipeline when the slurry velocity falls below a certain critical threshold value, indicating a material phase change from cohesive-viscous to cohesive-frictional. In a previous study of radial flow through disks, complete analytical solutions of the requ...

This study demonstrates how high-resolution X-ray computed tomography can be used to determine the geometry of curved inclusion trails in garnet porphyroblasts. For the first time, the three-dimensional geometry of these features is shown as an animation, a stereo pair, a VRML model, and two-dimensional sections. The spatial resolution of the data in this study, approximately 10 μm, is high enough to resolve inclusions, and finer resolutions are possible. Comparisons of scan imagery with thin section and microprobe data demonstrate that many typical inclusion phases in garnet porphyroblasts can be clearly distinguished, including quartz, ilmenite, and monazite. A sodium metatungstate solution with a density of 1.19 g/cm³ was used for a wedge calibration during scanning, reducing artifacts to a minimum and allowing maximum image contrast. The overall conclusion of this study is that high-resolution X-ray computed tomography is a quick, non-destructive technique that is invaluable in the study of porphyroblast microstructure. The three-dimensional data generated by this technique can be compared with geometries predicted by the varying theoretical models for the formation of curved inclusion trails in garnet porphyroblasts. They can also be analyzed to determine the three-dimensional orientation of curvature axes in individual porphyroblasts, which has not been possible until now.